Clearance between Powerlines and Vegetation

Clearance between power lines and vegetation is dependent on the type of construction, the voltage level and the physical location of the lines. The distances are defined in the Electricity (Principles of Vegetation Clearance) Regulations 1996 .

The Technical Regulator is responsible for administering the requirements of the Vegetation Clearance Regulations and ensuring the achievement and maintenance of the prescribed clearance distances in accordance with Section 5 of the Electricity (Principles of Vegetation Clearance) Regulations 1996 . The Technical Regulator is also responsible for determining disputes if the electricity entity and local Council fail to agree on vegetation clearance.

Vegetation such as trees and bushes cannot be planted and nurtured within the prescribed minimum safety clearance zone for power lines. The Technical Regulator has produced a brochure 'Trees and Powerlines' which further explains these requirements.

Risks Associated with Vegetation Clearances

The risks directly associated with vegetation contacting high voltage powerlines are:

• Electric shock if the bark is wet and someone touches the tree.
• Fire at the point of contact between the powerline and vegetation.
• Fire caused by clashing of wires and the resulting sparks and molten metal falling to the ground, which can have serious consequences in bushfire risk areas.
• Electric shock to a person climbing a tree and coming in contact with live wires.
• Damage to powerlines resulting in live powerlines falling to the ground.
• Damage to powerlines resulting in high voltage power lines falling onto low voltage lines causing flashovers and power surges.
• Damage to power lines resulting in interruption of supply.

To protect people and property from these risks, clearance zones, buffer zones and planting restrictions have been established in Regulations under the Electricity Act.

This is an example of the type of incidents that can occur with trees growing through power lines: A report was received from a rubbish truck operator of an electric shock he had from his truck. When this incident was investigated it was found that the truck was in contact with a tree, which in turn was in contact with a live power line.

Vegetation Clearance Complaints

On numerous occasions the Technical Regulator is required to act as a mediator between the owners of trees requiring trimming and an electricity entity. Usually in these cases, an explanation of the requirements of the legislation, as part of an education process, and involvement of the electricity entity horticulturist facilitates a mutually acceptable outcome. The Technical Regulator also responds to vegetation clearance issues directed to the Minister.

Vegetation Clearance Agreements

The Electricity Act 1996  states that an electricity entity has a duty to keep all kinds of vegetation clear of public power lines. The Act also makes provisions for electricity entities and councils to enter into vegetation clearance agreements. Under the scheme the vegetation clearance duties are conferred onto a council. Electricity entities (the transmission network operator and the distribution network operator) conduct annual inspections of their assets to verify compliance with the requirements of the Electricity Act and the Regulations.